The present invention relates to the field of optical phase sensitive detection.
It would be highly desirable to provide a technique which employs optical phase sensitive detection in numerous applications which previously benefitted from electronic phase sensitive detection. In addition, since optical phase sensitive detection can be applied to two-dimensional data such as images, massive parallel phase sensitive detection schemes could be employed to great advantage. For example, image multiplexing could be done by encoding numerous images at different frequencies in the same input channel. Using optical phase sensitive detection, the images can be easily separated out, thereby enabling real time video information to be transmitted in audio bandwidth channels. A special case would be an image comprising a large array of dots, each representing separate audio channels. This could be modulated with a GHz carrier frequency to increase effective data rates per unit bandwidth. This would be especially useful for images transmitted in coherent fiber bundles, where it should be possible to utilize the full optical bandwidth available. Applications to digital communication systems will increase throughput rates by taking advantage of the massive parallelism inherent in our novel technique.
Thus, two-dimensional phase shift keying can be realized using spatial light modulators (SLMs) to encode symbols in matrix form, and optical phase sensitive detection can be used to demodulate the symbol matrix. Further extensions to two-dimensional digital communication systems can be made such as frequency shift keying where coherent detection is important.